Coextrusion Blow Molding of Large Parts
Coextrusion is used extensively in small bottles and containers, but increasingly also for large blow molded parts (18.92 liters or 5 gallons and larger). Its growth, however, is very healthy and will accelerate in the coming years because of the need for recycling of plastic and the application of this technology to manufacture of products requiring improved barrier properties.

Three-Dimensional Blow Molding
The three-dimensional blow molding concept was developed several years ago in Japan. The most successful of these technologies is the Placo X-Y machine which moves the mold under the head [2]. There are many advantages to three-dimensional blow molding, including minimal flash, seamless parts, and sequential extrusion. Many complex shapes can be easily produced using the three-dimensional blow molding process. At this time, process options for three-dimensional molding: X-Y process, suction blow molding, and curved blow molding are offered by Krupp (add a link to Krupp.

Hard-Soft-Hard and Soft-Hard-Soft Technology
It has been shown that a combination of various materials imparts specific properties to a part in extrusion blow molding. Here, the extruded parison is built up in a radial direction by several overlaying layers (traditional or radial coextrusion). New in practical application, however, is the use of various materials in the axial direction, that is, specific article sections may be provided with specific properties by choosing corresponding materials.

Long-Glass-Fiber-Reinforced Blow Molding
The use of short-glass-fiber-reinforced thermoplastics (mainly PA 6, PA 6.6, and PP) with medium fiber lengths between 0.2 and 0.4 mm (0.007 in. and 0.0156 in.) has been known for some time. Unfortunately it was impossible to realize improvements in tensile strength, modulus of elasticity, and deflection temperature under load in the order hoped for by using glass fibers. The reason was the insufficient length of the fibers, which was reduced substantially from its original length as a consequence of the shearing action in the extruder.

Blow Molding Foam Technology

Krupp Kautex, Borealis, and OBG Design introduced foam technology, based on a patent held by leading equipment manufacture Krupp Kautex (Patent Number US 4.874.649). A special-recipe mastermix from Borealis, a major polylefin producer, allows highly reliable processing and consistent results.